Pivoted blade dampers are well known and in common use, but for many years it was not possible to employ a construction which was easy to build, reliable to operate, and easy to service. These needs to a considerable extent were satisfied by the slidable mounting pin construction disclosed in my prior U.S. Pat. No. 4,355,567 issued Oct. 26, 1982.
The slidable mounting pins and the combination of these pins with a pivoted blade disclosed in said patent are now in widespread use in commerce. However, some difficulties have been encountered when the pin-receiving depression in the central portion of the pivoted blade is of V-shape because when the nut and bolt used to secure the pin within the pin-receiving depression is excessively tightened, the pivoted blade can be deformed and/or the pin can be bent which leads to misalignment of the blades in the damper. As should be evident, the misaligned blades will not seat properly, so the damper will leak or jam, which wastes energy and can damage equipment.
Damper blades having a centrally positioned pin-receiving depression of V-shape are particularly easy to provide, being formable by merely bending the blade using the commonly available brake. This is why damper blades of this configuration are most commonly used in commerce. Nonetheless, the art has not been able to overcome the distortion of the damper blades having a V-shaped pin-receiving depression, instead electing to position the cylindrical pin disclosed in my prior patent and to tighten the nut and bolt used to secure it as carefully as possible. Nonetheless, some workmen are better than others, and it is desired to avoid the distortion which sometimes resulted.
In an effort to ease the distortion problem, the art has employed blades of special construction, but this introduces undesired expense which is avoided by this invention.